Space · Moons
Naiad
A moon of Neptune — Neptune's innermost moon — orbits inside the synchronous orbit and spirals inward.
Quick facts
Parent planet
Diameter (mean)
66 km
Mass
1.94 × 10¹⁷ kg
2.64e-06 Moon masses
Mean orbital radius
48,227 km
Orbital period
0.294 Earth days
Discovery year
1989
Discoverer
Voyager 2 imaging team
Naming origin
Greek water nymphs
Surface conditions
Naiad is the innermost moon of Neptune, orbiting at just 48,227 km. Its orbit is inside Neptune's synchronous orbital radius, so tidal interactions are gradually pulling Naiad inward. The moon's orbit is also unusually tilted, suggesting past gravitational interactions with other inner moons.
Missions and observations
Every Neptune-system mission has had an opportunity to image or characterize Naiad. The list below is the Neptune-system mission catalog; specific Naiad encounters are documented in mission archives.
| Mission | Year at Neptune | Status |
|---|---|---|
|
Voyager 2 NASA |
1989 | Completed |
Naming etymology
Naiads were the freshwater nymphs of Greek mythology, daughters of Zeus or the river gods. Adopted by the IAU in 1991.
Methodology & sources
Diameter, mass, and orbital parameters from JPL Solar System Dynamics — Physical Parameters. Discovery year and discoverer from the JPL Satellite Discovery Circumstances. Naming etymology from the IAU Working Group for Planetary System Nomenclature. Stylized SVG hero composed from NASA / JPL imagery as visual reference; no photographs are reproduced.